[FFmpeg-devel] [WIP][RFC][PATCH] png: support for skiping decoding data

Paul B Mahol onemda at gmail.com
Mon Aug 12 11:21:44 CEST 2013

On 8/10/13, Paul B Mahol <onemda at gmail.com> wrote:
> On 8/10/13, Nicolas George <nicolas.george at normalesup.org> wrote:
>> Le duodi 22 thermidor, an CCXXI, Paul B Mahol a ecrit :
>>> Crude attempt at parsing only frame and not doing decoding.
>>> It returns frames with data, not calling ff_get_video_buffer()
>>> gives error.
>>> Perhaps doing this from parser is better solution.
>> I suppose this is about trac ticket #2845 and this recent discussion in
>> -user:
>> http://ffmpeg.org/pipermail/ffmpeg-user/2013-August/016685.html
>> I see you are using AVDISCARD_ALL to implement this; it does seem like a
>> good idea, but did you check whether the few codecs that support it
>> handle
>> it the same way? Ideally, this option could be enabled in
>> avformat_find_stream_info() for all codecs.
> What exactly you mean by this? Decoding single packet and use what is
> in codec context?
> Codecs that use AVDISCARD_ALL do not return frames at all, so that is why
> I seek for better solution.
> But how would one handle case when width/height/format changes midstream?

I can freely assume by silence that this approach is good, but I just
need to use something other than AVDISCARD_ALL.

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